Part # LM2640 datasheet

Part Manufacturer: National Semiconductor

National Semiconductor

Part Description:

Part Details:

LM2640 May 2001 Dual LM2640Dual Adjustable Step-Down Switching Power Supply Adjustable ControllerGeneral Description Key Specifications The LM2640 is a dual step-down power supply controller n 96% efficient intended for application in notebook personal computers and n 5.5 to 30V input range other battery-powered equipment. n Dual outputs adjustable from 2.2 to 6V Step-Down Fixed-frequency synchronous drive of logic-level N-channel n 0.5% typical load regulation error power MOSFETs is combined with an optional n 0.002%/V typical line regulation error pulse-skipping mode to achieve ultra efficient power conver-sion over a 1000:1 load current range. The pulse-skipping Features mode can be disabled in favor of fixed-frequency operationregardless of the load current level. n 200 kHz fixed-frequency switching High DC gain and current-mode feedback control assure n Switching synchronization with an external signal up to 400 kHz excellent line and load regulation and a wide loop bandwidth Switching for fast response to dynamic loads. n Optional pulse-skipping mode An internal oscillator fixes the switching frequency at n Adjustable secondary feedback 200 kHz. Optionally, switching can be synchronized to an n Input undervoltage lockout external clock running as fast as 400 kHz. n Output undervoltage shutdown protection An optional soft-start feature limits current surges from the n Output overvoltage shutdown protection input power supply at start up and provides a simple means n Programmable soft-start (each controller) of start-up sequencing. n 5V, 50 mA linear regulator output Power Logic-level inputs allow the controllers to be turned ON and n Precision 2.5V reference output OFF separately. n 28-pin TSSOP Applications Supply n Notebook and subnotebook computers

Please click the following link to download the datasheet:

LM2640.pdf Datasheet